package ctrlserver

import (
	"errors"
	"fmt"
	"math/rand"
	"net"
	"strconv"

	"github.com/tim-beatham/wgmesh/pkg/lib"
	"golang.zx2c4.com/wireguard/wgctrl"
	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
)

/*
 * Create a new control server instance running
 * on the provided port.
 */
func NewCtrlServer(wgClient *wgctrl.Client, ifName string) *MeshCtrlServer {
	ctrlServer := new(MeshCtrlServer)
	ctrlServer.Meshes = make(map[string]Mesh)
	ctrlServer.Client = wgClient
	ctrlServer.IfName = ifName
	return ctrlServer
}

/*
 * Given the meshid returns true if the node is in the mesh
 * false otherwise.
 */
func (server *MeshCtrlServer) IsInMesh(meshId string) bool {
	_, inMesh := server.Meshes[meshId]
	return inMesh
}

func (server *MeshCtrlServer) addSelfToMesh(meshId string) error {
	ipAddr := lib.GetOutboundIP()

	node := MeshNode{
		HostEndpoint: ipAddr.String() + ":8080",
		PublicKey:    server.GetDevice().PrivateKey.String(),
		WgEndpoint:   ipAddr.String() + ":51820",
		WgHost:       "10.0.0.1/32",
	}

	server.Meshes[meshId].Nodes[node.HostEndpoint] = node
	return nil
}

func (server *MeshCtrlServer) CreateMesh() (*Mesh, error) {
	key, err := wgtypes.GenerateKey()

	if err != nil {
		return nil, err
	}

	var mesh Mesh = Mesh{
		SharedKey: &key,
		Nodes:     make(map[string]MeshNode),
	}

	server.Meshes[key.String()] = mesh
	server.addSelfToMesh(mesh.SharedKey.String())
	return &mesh, nil
}

type AddHostArgs struct {
	HostEndpoint string
	PublicKey    string
	MeshId       string
	WgEndpoint   string
}

func (server *MeshCtrlServer) AddHost(args AddHostArgs) error {
	nodes, contains := server.Meshes[args.MeshId]

	if !contains {
		return errors.New("Node does not exist in the mesh")
	}

	_, contains = nodes.Nodes[args.HostEndpoint]

	if contains {
		return errors.New("The node already has an endpoint in the mesh network")
	}

	fmt.Println(args.WgEndpoint)

	node := MeshNode{
		HostEndpoint: args.HostEndpoint,
		WgEndpoint:   args.WgEndpoint,
		PublicKey:    args.PublicKey,
		WgHost:       "10.0.0." + strconv.Itoa(rand.Intn(253)+1) + "/32",
	}

	err := AddWgPeer(server.IfName, server.Client, node)

	if err == nil {
		nodes.Nodes[args.HostEndpoint] = node
	} else {
		fmt.Println(err.Error())
	}

	return err
}

func (server *MeshCtrlServer) GetDevice() *wgtypes.Device {
	dev, err := server.Client.Device(server.IfName)

	if err != nil {
		return nil
	}

	return dev
}

func AddWgPeer(ifName string, client *wgctrl.Client, node MeshNode) error {
	peer := make([]wgtypes.PeerConfig, 1)

	peerPublic, err := wgtypes.ParseKey(node.PublicKey)

	if err != nil {
		return err
	}

	peerEndpoint, err := net.ResolveUDPAddr("udp", node.WgEndpoint)

	if err != nil {
		fmt.Println("err")
		return err
	}

	allowedIps := make([]net.IPNet, 1)
	_, ipnet, err := net.ParseCIDR(node.WgHost)

	if err != nil {
		return err
	}

	allowedIps[0] = *ipnet

	peer[0] = wgtypes.PeerConfig{
		PublicKey:  peerPublic,
		Endpoint:   peerEndpoint,
		AllowedIPs: allowedIps,
	}

	cfg := wgtypes.Config{
		Peers: peer,
	}

	err = client.ConfigureDevice(ifName, cfg)

	if err != nil {
		fmt.Println(err.Error())
	}

	dev, err := client.Device(ifName)

	fmt.Println("Number of peers: " + strconv.Itoa(len(dev.Peers)))

	if err != nil {
		return err
	}

	return nil
}